A vehicle is provided with various control systems in order to make the vehicle move properly. Because the wheel loads of the wheels are sometimes used as control parameters in such a control system, these wheel loads need to be estimated accurately. For example, in an automatic brake control system, an appropriate braking force is distributed in accordance with the wheel load of each wheel.
JP 2004-317443A focuses on the establishment of a certain relationship between the air pressure of a tire, deflection of the tire (elastic deformation amount), and a wheel load, and discloses a method for estimating the wheel load based on the air pressure and the deflection of the tire.